Checking status after sending scheduler command

[buuuudzik]

I think that scheduler could have possibility to define in command the status of another group adress which is checked after some defined offset. Because it is possible that command was sent but on the bus there was too much traffic and command was not received by destination device. I haven't already such situation but I think that with such additional tool scheduler would be more reliable. Maybe users won't use this function in every scheduler but when there will be a need for special reliability.